1. Field of the Invention
The present invention generally relates to equipment employed in a fuel system. The present invention more specifically relates to an apparatus and associated method for filtering fuel in a fuel system, such as a gas turbine fuel system.
2. Description of the Prior Art
Apparatus and methods for filtering a variety of fluids and liquids have been known in the art.
U.S. Pat. No. 3,179,253 to McNeal discloses a strainer comprising a casing having a removable cover secured to the casing by bolts. This patent describes a strainer which is stated to be particularly useful for water supply systems for large industrial plants which draw directly from a river or other source of supply which may contain a considerable amount of rubbish such as sticks, leaves and other debris.
U.S. Pat. No. 5,213,596 to Kume et al. discloses an air cleaner device which includes a filter element for filtering air. The housing of this device has an inlet and outlet and a flow passage in communication with the inlet and the outlet.
U.S. Pat. No. 5,632,793 to Haggard discloses a filter assembly stated to be formed of an impervious elongated tubular housing with an elongated filter member positioned within the housing. This patent describes air flowing into the housing inlet and through the filter member before exiting at the outlet end.
U.S. Pat. No. 2,893,563 to Bottum discloses a strainer construction including a tube, a cone-shaped screen, and a coil-shaped mounted spring. This patent states that assembly of the spring and screen into the body of its tube generally requires the use of a hand tool.
U.S. Pat. No. 4,961,847 to Amr discloses a suction strainer for use with a fluid machine. This patent discloses a suction strainer assembly comprising a housing which includes a tee-shaped structure having an inlet and outlet and a single strainer apparatus.
Canadian Patent 604,494 is described as a filter and more particularly to a dry type gas filter. The filter unit of this patent comprises a housing formed of a cylindrical casing having air inlet and outlet apparatus, and a removable cover member seated over the filter element enclosed in the housing.
U.S. Pat. No. 5,229,078 to Haerle discloses a filter for the separation of impurities or contaminants from a fluid or gas use medium. This patent also discloses a filter body having a plurality of inlet and outlet channels, whereby the inlet channels are separated from the outlet channels by filter walls which form reaction spaces.
U.S. Pat. No. 5,269,824 to Takita discloses a generally flat air filter device for an optical disc drive. This patent discloses a filter including a filter mat which removes dust and other impurities from the air and which has a generally "V" shaped section.
U.S. Pat. No. 5,704,957 to Rutz discloses a powder barrier with a filter element of microporous material for use with an air injector in a powder feeder of a powder coating system.
U.S. Pat. No. 2,910,717 to Raymond discloses a vacuum cleaner hose attachment. This patent teaches attachment which is stated to be effective for pulsating a flow of air into the vacuum cleaner hose. An apparatus is also disclosed in this patent for straining the air entering the vacuum cleaner hose and providing a visual indication of the operation of the attachment.
What is needed, however, is an apparatus which will provide an in-line installation of a filter which is insertable and removable without significant disruption of the fuel system in which it is employed, such as in a gas turbine. An apparatus is needed which has the potential for high temperature applications, and which does not provide significant resistance or back pressure to fuel flow in the fuel system. Furthermore, what is also needed is a fuel filter apparatus which provides for accessible, manual removal of a filter element from the filtering apparatus without also requiring removal of the housing of the filtering apparatus from the fuel system.
As a result, in spite of existing fluid and liquid filtering technology, there remains a real and substantial need for a fuel system filtering apparatus which will minimize the problems associated with conventional fuel filter design and its resultant functionality.